Thesis vs. Topic
As you begin to formulate a thesis for your essay, think about the following distinction between topic and thesis. A topic is a general area of inquiry; derived from the Greek topos (place), "topic" designates the general subject of your essay. For instance, "the use of imagery in Swift's 'A Description of the Morning'" might be a topic of an essay. From a topic, many specific theses can be extracted and developed. A thesis is more specific and delimited; it exists "within" your topic. In your essay, you need to use an argumentative thesis.
In argumentative writing, the writer takes a stance and offers reasons in support of it. Crucial to any piece of argumentative writing is its thesis. The thesis arises from the topic, or subject, on which the writing focuses, and may be defined as follows:

A thesis is an idea, stated as an assertion, which represents a reasoned response to a question at issue and which will serve as the central idea of a unified composition.

If we've selected imagery as a topic, we might ask: why these particular images? To what end does Swift use the images he has chosen? One possible thesis is:

Swift's images emphasize the muck of the material world in order to direct attention to the class differences upon which London society depends.

When you compose a thesis statement, think about how it satisfies the following tests:

Is it an idea? Does it state, in a complete sentence, an assertion?

Does it make a claim that is truly contestable and therefore engaging?
(Yes, because one could also argue that the imagery works towards a different effect.)

Are the terms you are using precise and clear?
(Key terms here seem to be: "images," "the muck of the material world," "class differences," and the fact these differences help to maintain society.)

Has the thesis developed out of a process of reasoning?
Once these questions have been satisfactorily answered, use the resulting thesis to organize your evidence and begin the actual writing. As you do so, bear in mind the following questions:

What is my purpose in writing? What do I want to prove?
(Notice the explicit purpose in the thesis statement: it does not merely point out the fact that the poem's images tend to be visceral and grounded in the material world; instead, the thesis identifies these qualities, and then answers the question "So what?" The thesis tells us to what end the poem uses this kind of imagery.)

What question(s) does my writing answer?

Why do I think this question is important? Will other people think it equally important?

What are my specific reasons, my pieces of evidence? Does each piece of evidence support the claim I make in my thesis?

Where does my reasoning weaken or even stop? Am I merely offering opinions without reasoned evidence?


How can I best persuade my reader?